Been nearly three months round these parts since we updated the pound-for-pound top 20 list of the best boxers in the world regardless of weight, which is informational about how the sport has been going: It means not much has happened to warrant significant changes. But as four men who were on the list to start 2013 have fought since, including one last weekend, now's as good a time as any. It's also just an excuse to catch up with the latest comings and goings of boxing's elite practitioners, a number of whom will be occupied between now and the next regularly scheduled update about every two months or so.

Here's the most recent past update, for comparison's sake. You'll notice our #20, featherweight Orlando Salido, is out after his loss to Mikey Garcia. But gee, I wonder who will replace him? Life is such a mystery.

As usual, the dominant criterion is quality wins, especially of recent vintage. Other criteria, such as the "eyeball test," factor in around the periphery.

1. Floyd Mayweather, welterweight

He'll fight in May against a quality welterweight, the below-mentioned Robert Guerrero, in what could solidify his standing at a time when some folk have Andre Ward ahead of him. It will probably depend on how he fares. His inactivity makes him vulnerable to being passed, but maybe his big new Showtime deal will change all that.

2. Juan Manuel Marquez, welterweight

Marquez is looking at Timothy Bradley for his next fight, unless it's all a pump-fake to drive up his asking price for another Manny Pacquiao clash, and either would be a swell for his overall p4p credentials rather than this list, because I can't see Marquez passing Mayweather based on their meeting. He's lower on some other lists, though.

3. Andre Ward, super middleweight

Ward was looking like LeBron to Mayweather's Kobe, but these days he's more like Kyrie. If he could stay healthy, he would be a bigger p4p force, but he can't so he isn't yet. No word on his next fight — word is he's on the mend from his shoulder injury, but he's been in the news more lately for a media sparring session with Mayweather.

4. Sergio Martinez, middleweight

Since we typically do these updates every two months, Martinez figures to get into the next update because he's got a late-April meeting with Martin Murray. It'll be a test of the middleweight champion's dinged-up knee more than a bout that can move him up or keep him from moving down, even though Murray is a legit top-10 at 160.

5. Nonito Donaire, junior featherweight

Now here's a guy who could move up. Next month, 122-pound lineal champ Donaire is taking on the #1 contender in his division, Guillermo Rigondeaux, and if he wins without any controversy, it'll be hard to keep him below Martinez. He's also in the news for parting ways with Victor Conte, a boost to his image even though Conte quit.

6. Manny Pacquiao, welterweight

Pacquiao wants revenge on Marquez, but it's not clear when he'll get it. Every month or so, we seem to hear about what he might do next and how he might take an interim bout while waiting for Marquez, but I'd bet on inactivity until the fall. Since Top Rank is finally holding a card in Macau, talk of Pacquiao fighting there is getting believable.

7. Carl Froch, super middleweight

He's rematching Mikkel Kessler in late May, so don't count on him making the next update. By then, there's a chance he could be leapfrogged by someone, particularly Abner Mares. I still maintain that Froch is wildly undervalued on p4p lists because he is a little crude by comparison to the stereotypical p4p ideal.

8. Wladimir Klitschko, heavyweight

Klitschko is the dominant heavyweight of this era and hasn't beaten anyone even close to as good as his best win, over David Haye. That's why he's #8, and it's why he'll always be vulnerable on this p4p list. His next opponent, in early May, is Francesco Pianeta, for crissakes. I bet there are hardcores who had never heard of him.

9. Abner Mares, junior featherweight

As Mares is moving up in weight yet again to take on featherweight Daniel Ponce De Leon on the Mayweather undercard, a win could soon find him a couple spots higher on this list. It remains remarkable how murderous Mares' schedule has been the last few years, the only strength of schedule that compares with Froch's.

10. Brian Viloria, flyweight

Viloria's also been on a pretty impressive run against quality foes the past couple years, but he's taking a slight dip in April in Macau against Juan Francisco Estrada. Estrada gave junior flyweight Roman Gonzalez all he could handle, but four pounds can be the world in the lighter classes, and Viloria's better and more versatile than RG.

11. Timothy Bradley, welterweight

My pals over at the TBRB saw fit to dock Bradley for his near-loss to a lower-level Ruslan Provodnikov last weekend, and it's a reasonable call based on the eyeball test, but he stayed put here cuz, well, he won.

12. Vitali Klitschko, heavyweight

Bradley might be in trouble soon if Vitali was doing anything. Vitali isn't doing ANYTHING. He's just chilling out, thinking of quitting, not in any hurry to make up his mind apparently.

13. Bernard Hopkins, light heavyweight

However limited Tavoris Cloud is, Hopkins beat him, a clear top five fighter in his division, as an underdog at age 48. That warrants a bump up of several spots.

14. Adrien Broner, lightweight

Broner, don't "bite" people. "Fight" people. He doesn't move up for beating Gavin Rees, and won't fight again for a bit and might end up in some kind of promotional snafu in the meantime.

15. Robert Guerrero, welterweight

Obviously, beating Mayweather would do wonders for his p4p fortunes. More likely, we'll be debating shortly afterward whether he was competitive enough in a loss to remain in the top 20.

16. Brandon Rios, junior welterweight

A repeat this month of his victory over Mike Alvarado won't likely convince skeptics of my appointment of Rios here, but however rough he is around the edges, he wins.

17. Chad Dawson, light heavyweight

Dawson is looking at a dangerous fight in June against Adonis Stevenson. I'd give Dawson some p4p props for that win, even if Stevenson is moving up in weight.

18. Roman Gonzalez, junior flyweight

Had Gonzalez gotten the fight with Kazuto Ioka and won, he could've been climbing. Instead he didn't and doesn't have anything scheduled, either.

19. Mikkel Kessler, super middleweight

He beat Froch the first time, and he clearly still has some power and ability. But as good as the match-up is, it's hard to imagine Kessler beating Froch again.

20. Austin Trout, junior middleweight

This spot was a toss-up with Mikey Garcia, but Trout beat a more acclaimed p4per Miguel Cotto, so he gets the narrow edge. He can cement the spot or advance with an April win over Canelo Alvarez.

CHAMPIONS

The Transnational Boxing Rankings Board champions are the true lineal champions of each division, like in earlier years of boxing when there was only one champion per division. For more on lineal champions vs. titleholders, click here.